1. Field of the Invention
The present invention relates to a laminated core for an electromagnetic device.
2. Description of Related Art
Previously, various laminated cores, which use amorphous alloy instead of magnetic steel, have been proposed to reduce an iron loss (particularly, an eddy current loss) in an electromagnetic device, such as an electric motor, a transformer.
For example, Japanese Unexamined Patent Publication No. H06-292326 discloses one such core (laminated core). In this core, amorphous alloy plates are stacked one after another in a stacking direction to form a laminated body. This laminated body is clamped between two support plates in a direction perpendicular to the stacking direction.
Furthermore, in an article “Performance of Motor Using Amorphous Alloy Laminated Core” recited at pages B2-2-1 to B2-2-10 of a published textbook of 13th Applied Magnetic Technology Symposium dated Apr. 20, 2005, Chiba et al. teaches a technique where amorphous alloy plates (amorphous alloy thin films), each of which is coated with heat-resistant resin adhesive on one side thereof, are stacked together to form a laminated core. That is, the resin layer is interposed between each adjacent two amorphous alloy thin films in the laminated core.
In the laminated core of Japanese Unexamined Patent Publication No. H06-292326, the laminated body is clamped between the two support plates in the direction perpendicular to the stacking direction of the laminated body. Furthermore, in the clamped state where the amorphous alloy plates are clamped between the two support plates, windings are wound around the laminated core to hold the amorphous plates and the two support plates together. Thus, the amorphous alloy plates are not securely fixed together in the stacking direction, and thereby, such a core may not be suitable in a device, such as an electric motor, in which a mechanical torque is applied to the core.
Furthermore, in the above technology disclosed by Chiba et al. in the article “Performance of Motor Using Amorphous Alloy Laminated Core”, a space factor (a ratio of a total volume of the amorphous alloy plates in the entire volume of the laminated core) is reduced due to the presence of the resin layers in the laminated core, so that it may have adverse influences on the function of the laminated core.
Furthermore, the inventors of the present application have tried to weld amorphous alloy plates from a lateral side of the core. However, a crack is disadvantageously generated around the welded parts of the amorphous alloy plates.